A laboratory study of collapse behaviour of remoulded loess under controlled wetting and flooding

This paper presents the effect of initial placement conditions and flooding stress (vertical compressive stress at flooding) on the collapse potential of remoulded loess. Compacted specimens of loess were tested in a one-dimensional consolidometer to study the collapse behaviour. Initial water content, dry unit weight and flooding stress were varied. Collapse potential was found to be dependent on initial water content, initial dry unit weight and flooding stress. Partial collapse was studied by allowing measured increments of water into the specimens.     

传感器放置深度对水温动态特征的影响及其机理分析

地热井的观测规范要求尽可能将水温传感器放置在井下深处, 一般放置深度应当大于100 m, 小于200 m。 然而, 近几年的观测结果表明, 水温传感器的放置深度对水温动态特征的影响较大。 在多数观测井中, 同井水温与水位的时值动态、 潮汐效应、 同震响应及震后阶变等动态特征的相关性或一致性, 多与水温传感器的放置深度有关。 本文主要探讨了传感器放置深度对水温动态特征的影响, 水温传感器放置在观测含水层中, 都受井—含水层间水流运动的影响, 会造成水温动态随井水位变化而变化; 当放置在观测含水层下部时, 水温动态则不受井水位变化的影响, 多表现为动态相对稳定。 其原因是水温动态的形成受水热动力学与地热动力学两种不同机制的控制, 此外, 井—含水层系统的条件也会产生影响。     

Evaluating the Efficiency of Typographic Design: Gender and Expertise Variation

Abstract

Although the efficiency of label placement algorithms has been studied extensively, few studies considered the influence of the label designs on the efficiency of map readers. Labels are one of the most important elements on the map as they can provide more information than other symbols can. The design of the labels does have to stress the theme, shape and functionality of the associated objects, which results in a more efficient interpretation of the map content by the user. How the label designs can enhance the map readers’ efficiency (and thus the quality of the maps themselves) is the main objective of this study. A user study was conducted in which the participants were asked to locate a target label on a map. Different label designs were implemented across the trials. The participants’ reactions times were registered to measure their efficiency and statistically analysed using a one-way ANOVA. Two different users’ characteristics were considered: gender and expertise. Related to the size, shape, orientation and texture of the labels, a number of significant differences (P<0·05) and trends were located. Differences in efficiency between males and females, on the one hand, and between novices and experts, on the other hand, were also described statistically. Consequently, recommendations can be formulated regarding the design of labels in order to obtain more efficient maps, keeping in mind the map users’ characteristics.     

Investigating the Effectiveness of an Efficient Label Placement Method Using Eye Movement Data

Abstract

This paper focuses on improving the efficiency and effectiveness of dynamic and interactive maps in relation to the user. A label placement method with an improved algorithmic efficiency is presented. Since this algorithm has an influence on the actual placement of the name labels on the map, it is tested if this efficient algorithms also creates more effective maps: how well is the information processed by the user. We tested 30 participants while they were working on a dynamic and interactive map display. Their task was to locate geographical names on each of the presented maps. Their eye movements were registered together with the time at which a given label was found. The gathered data reveal no difference in the user’s response times, neither in the number and the duration of the fixations between both map designs. The results of this study show that the efficiency of label placement algorithms can be improved without disturbing the user’s cognitive map. Consequently, we created a more efficient map without affecting its effectiveness towards the user.     

Trace metals associated with deep-sea tailings placement at the Batu Hijau copper–gold mine,Sumbawa, Indonesia

The Batu Hijau copper–gold mine on the island of Sumbawa, Indonesia operates a deep-sea tailings placement (DSTP) facility to dispose of the tailings within the offshore Senunu Canyon. The concentrations of trace metals in tailings, waters, and sediments from locations in the vicinity of the DSTP were determined during surveys in 2004 and 2009. In coastal and deep seawater samples from Alas Strait and the South Coast of Sumbawa, the dissolved concentrations of Ag, As, Cd, Cr, Hg, Pb and Zn were in the sub μg/L range. Dissolved copper concentrations ranged from 0.05 to 0.65 μg/L for all depths at these sites. Dissolved copper concentrations were the highest in the bottom-water from within the tailings plume inside Senunu Canyon, with up to 6.5 μg Cu/L measured in close proximity to the tailings discharge. In general, the concentrations of dissolved and particulate metals were similar in 2004 and 2009.     

Adaptive multi-resolution labeling in virtual landscapes

Labeling plays an important role in map production, attaching specific texts to related geographic elements to provide clear environmental references. In three-dimensional geographical information systems (3DGISs), however, cluttering happens fairly commonly because of the unexpected overlapping and occlusion among labels and related objects, and results in an ambiguous and obscure environment. It generally also takes large computing power and memory to visualize spatial entities. Aimed at both unambiguous and efficient 3D map display, this article proposes an adaptive multi-resolution labeling method to deal with point, polyline, and polygon features labeling in a 3D landscape. It implements adaptive placement and view-driven label filtering without obscuring other visual features. The experiments indicated that the display of overlapping labels and label popping are reduced significantly with less computation burden while retaining the rendering quality.     

Damper placement optimization in a shear building model with discrete design variables: a mixed‐integer second‐order cone programming approach

Supplemental damping is known as an efficient and practical means to improve seismic response of building structures. Presented in this paper is a mixed‐integer programming approach to find the optimal placement of supplemental dampers in a given shear building model. The damping coefficients of dampers are treated as discrete design variables. It is shown that a minimization problem of the sum of the transfer function amplitudes of the interstory drifts can be formulated as a mixed‐integer second‐order cone programming problem. The global optimal solution of the optimization problem is then found by using a solver based on a branch‐and‐cut algorithm. Two numerical examples in literature are solved with discrete design variables. In one of these examples, the proposed method finds a better solution than an existing method in literature developed for the continuous optimal damper placement problem. Copyright © 2013 John Wiley & Sons, Ltd.     

黏滞阻尼器在单层网壳结构中的优化布置

目前采用黏滞阻尼器对单层网壳结构进行减振控制时,阻尼器最优布置位置通过试算确定。针对此问题,推导了地震作用下黏滞阻尼器耗能公式,提出了以能量比例系数为评价指标的阻尼器优化布置准则。以单层球面网壳和单层柱面网壳为例,对比分析了地震作用下分别采用优化布置准则与现有布置方式布置阻尼器时结构最大节点位移减振系数,验证了所提出优化布置准则的正确性及在单层球面网壳和单层柱面网壳中的适用性。     

地图点要素注记自动配置中聚类分组的蚁群算法应用

大规模点要素注记自动配置问题是地图注记的难点之一,主要受限于时间效率和注记配置质量。针对该问题,本文首先提出一种椭圆形多方位多级注记待选方位配置方案,使其参数化、多元化。其次,结合点要素空间分布特征,提出一种以聚类分组的蚁群算法,并讨论和优化核心参数,实现大规模点要素的注记快速配置。实验表明,该算法计算效率明显提升,算法性能稳定。针对注记密度在5%~30%随机分布点要素的地图,其相比传统蚁群算法算法效率提高73.2%;同时,该算法的注记结果质量比传统蚁群算法注记结果质量好,注记适应度提升8.0%。实验采用抚顺县集体土地所有权界址点数据进行验证,结果表明效率提升86.7%,且注记适应度提升14.6%。本算法适用于点要素规模大、点簇疏密变化差异大的点要素注记自动配置问题的快速求解。